The Baphomet, as seen here, drawn by Eliphas Levi,
the
19th century Freemason and Kabbalist magician, first gained notoriety
as a symbol of Satanism when, in the 14th century, the Knights Templar
were accused of
using the idol in occult rituals. Heimbichner,
author of Blood On The Altar, elaborates:

"Baphomet or Capricornus, the infernal 'god of lust,' is an androgynous
symbol combining animal and human qualities with male and female
characteristics, a dark incarnation of the essence of the Kabbalah.
The duality at the heart of the Kabbalah
is taught in higher Masonry and the OTO through the 'Tree of Life'
shchema of Rabbi Isaac Luria, which aligns the emanations of Adam Kadmon
into the Two Pillars ('Twin Towers'): the Pillar of Severity (the right)
and the Pillar of Mercy (the left). This symbol reflects the anceint
veneration of the twin orbits of the 'Dog Star' Sirius A and B, symbols
of the Double-Mind, the diable, the Devil or Set/An, or Satan."
(Craig Heimbichner, "The Kabbalah of the Cryptocracy", Paranoia magazine,
issue 41, Spring 2006, page 54)